Los Angeles County’s largest lake is kicking off the summer season! Castaic Lake’s recreational swim area is now open for visitors, and the massive Cali Splash inflatable water park is soon to follow.
Pack your sunscreen, prepare a picnic, and keep reading for everything to know before you hit the road.
Swimming at Castaic Lake
The Lower Lake’s designated Swim Beach only allows swimming when lifeguards are present, starting on the third weekend in May. Right now, swimmers can enjoy the recreational swim areas on weekends from 10 am to 6 pm, and then from Wednesday to Sunday beginning in June.
The popular Cali Splash Park opens for the summer on May 23, 2026, following the same opening hours as the swim areas. As SoCal’s largest inflatable aquapark, it features 45 epic floating obstacles and features.
Sessions are available every 2 hours with a 2-hour duration, or you can also purchase a full day or full season pass. Kids over 9 may participate alone, but an adult must accompany kids from 4-8 years old.
More summer activities at Castaic Lake
The Castaic Lake State Recreation Area includes both the Upper Lake and the Lower Lake lagoon, offering a combined 29 miles of shoreline.
Motorized water sports like jet skiing, wakeboarding, sailing, and power boating are reserved for the Upper Lake, while the Lower Lake is dedicated to non-motorized activities such as swimming, kayaking, canoeing, and paddleboarding.
Fishing is popular across both lakes, with anglers often catching bass, trout, and catfish—sometimes even record-breaking sizes. Favorite spots include the lagoon’s fishing pier and the east arm of the Upper Lake.
Beyond the water, visitors can explore more than seven miles of hiking and biking trails, enjoy picnic areas, or stay overnight with tent and RV camping equipped with amenities.
Keep in mind that Castaic Lake SRA is one of the few California State Parks that does not accept the Annual State Parks Pass.